Retrievable well packer apparatus



April 28, 1970 J. w. KISLING 3,508,610

RETRIEVABLE WELL PACKER APPARATUS Filed Sept. 27, 1968 2 Sheets-Sheet l(fir/77a: W. Huh/(@E' INVENTOR.

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I RETRIEVABLE WELL PACKER APPARATUS Filed Sept. 27, 1968 2 Sheets-Sheet2 24 99 H *2; /0/ a/wreJ W. Huh/7y, E

INVEN'I'OR ATTORNEY Patented Apr. 28, 1970 3,508,610 RETRIEVABLE WELLPACKER APPARATUS James W. Kisling III, Houston, Tex., assignor toSchlumberger Technology 'Corporation, New York, N.Y., a corporation ofTexas Filed Sept. 27, 1968, Ser. No. 763,150 Int. Cl. E21b 23/00 U.S.Cl. 166-120 Claims ABSTRACT OF THE DISCLOSURE The particular embodimentdisclosed herein as illustrative of one form of the present invention inwell packers comprises a body member and packing means for packing off awell bore, normally retracted slip means, expander means movabledownwardly relative to said slip means for expanding said slip meansinto anchoring positions against a well conduit wall, and hydraulicmeans including a plurality of piston members coupled in seriesrelationship to said expander means, each of said piston members haveupper and lower pressure surfaces subject to fluid pressure in the wellbore respectively below and above said packings means, so that greaterfluid pressure in the well bore below said packing means than above saidpacking means can act on said piston members conjointly to force saidexpander means downwardly to retain said slip means in anchoringnnsitions against the well conduit wall.

This invention relates generally to well tools used for packing off orisolating well bore zones, and more specifically to retrieva'ble wellpackers and plugs having expansible anchors and packing for preventingfluid movement in either direction past its sealing point.

To conduct testing, remedial, stimulation or production operations in aparticular zone in a well, the zone can be isolated by well tools whichcan be positioned in the well bore below and above the zone. The lowertool, com monly called a bridge plug, functions to seal off the entirecross-section of the well bore to isolate the zone from fluids at theirhydrostatic pressures which are below the zone. The upper tool, commonlycalled a packer, is generally retrievalble and functions to seal otf theannulus between a tubing string attached to the packer and the wellcasing to isolate the zone from fluids at their hydrostatic pressureswhich are above the zone. The tubing string provides a means of accessto the isolated zone for fluid flow, testing tools, or other instrumentswhich can be lowered therethrough. Although permanent type bridge plugshave been used for the lower tool, it has become common practice to useretrievable type bridge plugs which can be left in the well bore ifdesired, but which can also be retrieved to the surface for further andrepeated usage if desired.

Inasmuch as fluid pressure may be imposed on a bridge plug either fromabove or below, it is necessary to anchor the plug against movement inboth directions. In the past, such anchoring has been accomplished forthe most part by independently operable slips and expanders, one Slipand expander combination being arranged to prevent movement in onedirection and the other slip and expander combination coming into playto prevent movement in the other direction. A more recent advance in theart, shown in the 196869 Composite Catalog of Oil Field Equipment andServices, page 2755, enables only a single slip and expander combinationto prevent movement in both directions. This slip and expandercombination is mechanically set against movement in a downwarddirection, and a hydraulic system including a piston on the expanderwhich is responsive to greater fluid pressure below the plug functionsto hold the slips in set position, thereby preventing upward movement.

It is necessary, in order to provide adequate retaining force to theslips when the fluid pressure in the well bore below the packer isgreater, for the hydraulic system to have ample pressure areas on whichthe greater fluid pressure can act, because it will be appreciated bythose skilled in the art that the downward force on the expander is afunction of the pressure differential across the tool and the pressurearea of the piston. One solution to the problem of adequate pressureareas is disclosed in U.S. Patent No. 3,437,136 to Young, assigned tothe assignee of the present invention, wherein the body structure of thepacker has different diameter sections, the packing elements beingmounted on the larger diameter section and the piston being sealinglyslidable on the smaller diameter section. This arrangement enables thepiston to have an increased transverse area which is acted upon by thegreater fluid pressure in the well bore below the packing elements,resulting in an adequate downward force on the expander over a range ofsizes of tools.

The present invention is directed to the same problem of providingadequate pressure areas for the piston, and according to the concepts ofthe present invention, the hydraulic system includes a plurality ofpiston members which are coupled in series relationship to the expander.Each of the piston members has an upwardly facing presssure surfacewhich is subject to fluid pressure in the well bore below the packingelements, and a downwardly facing pressure surface which is subject tofluid pressure in the well bore above the packing elements. Each of thepiston members can be sealingly slidable on the same diametered portionof the body structure, and the downward force on the expander due togreater fluid pressure below the packing elements is amplified accordingto the number of piston members used. The present invention thus enablesselectivity of cone-holding response to provide adequate retaining forceon the slips over a wide range of easing sizes and tools.

The novel features of the present invention are set forth withparticularity in the appended claims. The invention, together with otherconcepts and advantages thereof, may be best understood by way ofexample of one embodiment thereof when taken in conjunction with thefollowing drawings in which:

FIGURE 1A is a sectional view of the upper portion of an apparatus inaccordance with the present invention with parts in relative positionsfor longitudinal movement in a well conduit;

FIGURE 1B is a view similar to FIGURE 1A showing the lower portion ofthe apparatus of the present invention and forms a lower continuation ofFIGURE 1A;

FIGURE 2A is a sectional view similar to FIGURE 1A but with parts intheir relative positions when the apparatus is set in a well conduit;and

FIGURE 2B is the lower continuation of FIGURE 2A.

In order to conduct remedia, stimulation or production operations in acased well bore which traverses a formation, it may be necessary toisolate a zone of the well bore adjacent the formation. This can beaccomplished by upper and lower packers releasably connected together bya running tool and lowered into the well bore on a pipe string. Thelower packer is set to plug the well bore at the lower end of the zone.Then the running tool is released from the lower packer and the upperpacker is elevated and set at the upper end of the zone. The pipe stringprovides a passageway from the earths surface through the upper packerand into the zone for fluid flow as well as various wireline or othertools. When the operation is completed,

3 the upper packer can be released and reconnected to the lower packer,which is then released so that both packers can be withdrawn from thewell or moved to another location in the well bore. The upper packer canbe constructed according to teachings of McGill, Patent No. 3,399,729,dated Sept. 3, 1968.

Referring now to FIGURES 1A and 1B for details of the lower packer,commonly called a retrievable bridge plug, apparatus in accordance withthe present inventioin includes a generally tubular body member ormandrel extending throughout the length of the tool. The body member 10has a central bore 11 which is opened at its lower end by several sideports 12. The upper end of the body member 10 is closed by a threadedlyattached connector head 13 having J-slots 14 or the like in its outerperiphery for connecting to a conventional running and retrieving tool(not shown).

A plurality of bypass ports 15 extend laterally through the wall of thebody member 10 below the connector head 13. Sealing elements 16 and 17are received in annular grooves above and below the ports 15. A sleevevalve 18 is slidably disposed on the body member 10 adjacent the ports15 and is movable between a lower position as shown in FIGURE 1A wherethe bypass ports 15 are open, and an upper position where the upper endof the sleeve valve 18 abuts the lower end of the connector head 13. Inthe upper position, the sleeve valve 18 spans the ports 15 and, incombinaiton with the sealing elements 16 and 17, functions to blockfluid flow therethrough. A plurality of spring fingers 19 extend fromthe lower end of the sleeve valve 18 and have enlarged head portions 20which are sized to engage an annular shoulder 21 formed on the bodymember to releasably hold the valve sleeve in either open or closedposition.

The body member 10 carries a generally tubular compression sleeve 24which has a downwardly facing shoulder or abutment 25. The abutment 25engages the upper end of a packing structure 26 which can be formed by aplurality of elastomeric rings 27 which are adapted, when compressed, tobe expanded into sealing contact with the well bore wall in a typicalmanner. The inner wall surface of the compression sleeve 24 is spacedlaterally away from the outer periphery of the body member 10 to providean annular fluid passageway 28. A suitable bearing 29 is mounted betweenan upwardly facing shoulder 30 on the compression sleeve 24 and adownwardly facing shoulder 31 on the body member 10 to reduce frictionalresistance to rotation of the body member within the compression sleeveunderloaded conditions. The passageway 28 is continued past the bearing29 by one or more radially cut and vertically disposed grooves 32.Coupled to the upper end of the compression sleeve 24 is a sleeveextension 33 having an inwardly extending shoulder 34 carrying a sealring 35, which is sealed against the periphery of the body member 10. Aninner sleeve 36 is positioned within the extension 33 and has an annularportion 37 which is sealed against the extension by a seal ring 38.Upper and lower ports 39 and 40 in the inner sleeve 36 and the extension33, respectively, are provided to communicate the vertical space 41 withthe passageway 28 and with the well annulus above the packing structure26. Thus, it will be apparent that the passageway 28 is always incommunication with fluids in the well annulus, and serves as atransmitting channel for the pressure of fluids in the well bore abovethe packing structure.

An expander cone 45 (FIGURE 1B) is mounted on the lower portion of thebody member 10 and has outer surfaces 46 inclining downwardly andinwardly toward the body member. Coupled between the expander cone 45and the packing structure 26 is a hydraulic assembly 47 including asleeve structure 48 extending upwardly from the expander cone andcoupled at its upper end to an inwardly extending piston member 49 whichis slidable on the lower portion 50 of the compression sleeve 24 andsealed with respect thereto by a seal ring 51. Another piston member 42is formed on the sleeve structure 48 intermediate its ends and alsoextends inwardly in sealing and sliding contact with the lower portion50 of the compression sleeve, fluid leakage being prevented by a sealring 53. An annular floating piston member 55 is movable between thebody member 10 and the sleeve structure 48 between an upper positionagainst an outwardly extending stop shoulder 56 on the body member, anda lower position where it rests on the expander cone 45. AppropriateO-rings or other seals 57 and 58 seal between the floating piston member55 and adjacent wall surfaces to prevent fluid leakage past the pistonmember.

The upper piston member 49 can engage above splines 59 on thecompression sleeve 24, such engagement limiting downward movement of thesleeve structure 48 and the expander cone 45 relative to the body member10, and the splines 59 engaging complementary splines 60 on the pistonmember 49 to prevent relative rotation between the compression sleeve 24and the sleeve structure 48. The piston member 49 supports a gauge ring61 which provides an upwardly facing abutment engaging the lower end ofthe packing 26. The gauge ring and piston member may be coupled againstrelative rotation by radially extending grooves and projections 62 and63 which also provide a fluid path to the upper end surfaces of thepiston member 49.

The lower portion 50 of the compression sleeve 24 extends downwardly toa location adjacent the upper surface of the stop shoulder 56 on thebody member 10. A separator piston 65 on the compression sleeve 24 issealed against the inner periphery of the sleeve structure 48 by a sealring 66, the piston 65 being located between the hydraulic pistonmembers 49 and 52. A port 67 communicates the upper face 68 of the lowerpiston member 52 with the well fluids in the annulus below the packing26, and as previously described, the upper surfaces of the upper pistonmember 49 are also subject to fluid pressure in the well bore below thepacking elements. Moreover, the passageway 28 between the compressionsleeve 24 and the body member 10 is in communication with the chamber 69formed between the lower piston member 52 and the floating piston member55, and via a port 70 with the chamber 71 formed between the upperpiston member 49 and the separator piston 65. Thus, it will beappreciated that the respective lower faces 72 and 73 of the upperpiston member 49 and the lower piston member 52 are in fluidcommunication with the well annulus above the packing 26 via thepassageways 28 and 41 and the various ports 39, 40 and 70.

A cage member is movably mounted on the lower end portion of the bodymember 10 above a stop flange 81. The cage member 80 has radiallydirected recesses receiving circumferentially spaced drag blocks 82which are urged outwardly by coil spring 83 into frictional contact withthe well casing. A plurality of wickered slip elements 84 can bepivotally coupled to the upper end of the cage member 80 by reins 85 orthe like, and are arranged for lateral movement between retracted andexpanded positions. The slip elements 84 have inner inclined surfaces 86which slidably engage the outer inclined surfaces 46 on the expandercone 45, and the slip elements can be slidably coupled to the expandercone by a conventional dove-tail tongue and groove connection 87.

A clutch assembly 90 is provided for controlling relative longitudinalmovement between the cage member 80 and the body member 10. The clutchassembly 90 includes a segmental clutch nut 91 which is received withinan internal annular recess 92 in the cage member, each of the nutsegments being secured against rotation relative to the cage member bylugs 93 which engage in peripheral slots in the segments. Upper andlower band springs 94 and 95 permit lateral movement of the nut segmentswhile continuously urging the segments toward contracted positionsaround the body member 10. Each nut segment can have upper left-handthreads 96 and lower right-hand threads 97 which are cooperable withcompanion threads 98 and 99 on the body section 26 to secure the bodymember relative to the cage member in spaced longitudinal positions. Aninwardly biased stop lug 100 can initially engage within a shoulderedrecess 101 in the mandrel to prevent counter-clockwise rotation of thecage member 80 relative to the body member during lowering, therebypreventing rotational locking of the lower end surface of the cagemember against the upper face of the gauge stop ring 81.

In operation, the parts can be assembled as shown in FIGURES 1A and 1Band lowered in the well casing to a location where it is desired to forma pressure bridge, for example, at the lower end of a zone to bepressurized. During lowering, a tubing string is connected to theconnector head 13 by a suitable running tool (not shown), andthe sleevevalve 18 is in its lower position where the bypass ports 15 are open.Thus, fluids in the well bore can bypass through the tool via the lowerports 12, the body bore 11 and the bypass ports 15, as well as aroundthe packing structure 26 to provide ample bypass area. During lowering,the lower threads 97 of the segmented clutch nut 91 are in engagementwith the lower body threads 99 to prevent upward movement of the cagemember 80 relative to the body member 10. The slip segments 84 are thusheld in retracted positions and cannot move upwardly to be shiftedoutwardly by the expander cone 45. The packing structure 26 is, ofcourse, retracted.

At setting depth, the tool is halted and the body member is torqued orturned several turns to the right by rotation of the tubing string.Inasmuch as the cage member 80 will not rotate due to frictionalengagement of the drag blocks 82 with the casing, rotation of the bodymember 10 will release the clutch nut threads 97 from the body threads99 to enable downward movement of the body member 10. Downward movementof the body member 10 by lowering the pipe string will cause thecompression sleeve 24, the packing structure 26 and the hydraulicassembly 47 to move downwardly, thereby bringing the expander cone 45behind the slip elements 84 and shifting the slip elements into grippingengagement with the well casing wall as shown in FIGURE 2B. The dragblocks 82 support the cage member 80 and the slips 84 against downwardmovement.

When, the slip teeth 102 are firmly engaged, the expander cone 45 andhydraulic assembly 47 are supported against further downward movement,thereby preventing further downward movement of the lower gauge ring orabutment 61. Accordingly, the weight of the tubing string can be imposedon the body member 10, causing downward movement of the compressionsleeve 24 and compression of the packing structure 26 between the upperabutment 25 and the lower abutment 61. Compression of the packingstructure will effect expansion of the elements 27 into sealingengagement with the casing wall. As the body member 10 moves downwardlyrelative to the cage member 80, the upper body threads 98 can ratchetthrough the upper clutch nut threads 96 which will trap the body memberin the lowermost position to which it is moved to lock the compressionenergy in the packing structure 26 and the slips '84 in set positions.The running tool can be released in a conventional manner which resultsin shifting the valve sleeve 18 upwardly to its closed position spanningthe ports 15. The tool is now set to hold pressure in either direction.

If a greater fluid pressure exists in the well bore above the tool, theslips 84 will be set even tighter against movement. Further, if agreater fluid pressure exists in the well bore below the tool, thegreater fluid pressure acts downwardly on the upper faces of the upperand lower piston members 49 and 42, while the lesser fluid pressureabove the tool is channeled to the lower faces 72 and 73 of the pistonmembers. As a consequence, the expander cone 45 is forced downwardlyrelative to the slips 84 to retain them in gripping contact with thecasing. The upward force on the floating piston 55 and the separatorpiston 65 is transferred by the body member 10, the clutch nut 91 andthe cage member to the slips 84 which are gripping the casing. Thus, thetool will not move in either direction in the well bore when fluidpressure is imposed upon it.

When it is desired to either retrieve the tool or to move to anothersetting location, the tubing string is lowered to engage the runningtool with the connector head 13. The sleeve valve 18 is automaticallypushed to its lower position where the bypass ports 15 are open toequalized fluid pressures across the packing structure 26. To releasethe slips 84 and the packing 26, the body member 10 is rotated severalturns to the right to release the upper clutch nut threads 96 fromengagement with the body threads 98. Then the body member is pulledupwardly to relieve the compression on the packing structure 26 so thatthe rings 27 will inherently retract. The splines 59 on the compressionsleeve 24 will engage the piston member 49 to pull the expander cone 45from behind the sli elements 84, thereby permitting their retraction. Asthe body member 10 reaches the upper limit of its travel relative to thecage member 80, the lower body threads 99 will ratchet into the lowerclutch nut threads 97 to lock the cage member 80 against movementrelative to the body member 10. The packer is then free to be movedlongitudinally in the well bore in either direction.

A new and improved well packer has been disclosed which can be anchoredagainst movement in either direction in a well bore. The packer includesa hydraulic structure for applying a holding force to the slips inresponse to greater fluid pressure in the well bore below the packer,the hydraulic structure including a plurality of piston members coupledin series relationship to the expander cone, each piston member havingupper and lower pressure surfaces which are subject to fluid pressure inthe well bore respectively below and above the packing elements.Accordingly, a greater well bore pressure below the packing than abovethe packing will act to force the expander downwardly to retain theslips set against movement in the casing. Although in the embodimentshown in the drawing two piston members are shown, it will be apparentthat more than two piston members could be used to amplify the downwardforce on the expander cone even greater.

Since certain changes and modifications may be made in the presentinvention by those skilled in the art without departing from theinvention concepts involved, it is the aim of the appended claims tocover all changes and modifications falling within the true spirit andscope of the present invention.

I claim:

1. A well packer apparatus comprising: a body structure having packingmeans thereon for packing off the cross-section of a well bore; normallyretracted slip means; expander means movable downwardly relative to saidslip means for expanding said slip means into gripping contact with thewell bore wall; and hydraulic means including a plurality of pistonmembers coupled in series relationship to said expander means, each ofsaid piston members having an upwardly facing pressure surface subjectto fluid pressure in the well bore below said packing means and adownwardly facing pressure surface subject to fluid pressure in the wellbore above said packing means, so that greater fluid pressure in thewell bore below said packing means than above said packing means acts onsaid piston members conjointly to force said expander means downwardlyto retain said slip means in gripping contact with the well bore wall.

2. A well packer apparatus comprising: a body structure; normallyretracted pacing means on said body structure adapted to be expanded insealing contact with a well bore wall; normally retracted slip means;expander means movable downwardly relative to said slip means forexpanding said slip means into gripping contact with a well bore wall;releasable means for securing said packing means and said slip means inexpanded positions; and hydraulic means responsive to greater fluidpressure in the well bore below said packing means for forcing saidexpander means downwardly relative to said slip means to retain saidslip means in gripping contact with a well bore wall, said hydraulicmeans including a plurality of piston members coupled in seriesrelationship, each of said piston members having an upwardly facingtransverse surface subject to fluid pressure in the well bore below saidpacking means and a downwardly facing transverse surface subject tofluid pressure in the Well bore above said packing means.

3. The well packer apparatus of claim 2 wherein said hydraulic meansfurther includes a sleeve structure extending upwardly from saidexpander means, each of said piston members being integral with saidsleeve structure and extending inwardly in sealing and sliding contactwith the outer periphery of said body structure.

4. The well packer apparatus of claim 3 wherein said sleeve structurehas port means for feeding fluid in the well bore below said packingmeans to one of said upwardly facing transverse surfaces of said pistonmembers.

5. The well packer apparatus of claim 4 further including passage meansfor feeding fluid in the well bore below said packing means to the otherof said upwardly facing transverse surfaces of said piston members.

6. A well packer apparatus comprising: a body member adapted to bereleasably coupled to a running-in string; a sleeve structuresurrounding a portion of said body member, said sleeve structure andbody member providing a fluid passageway therebetween; normallyretracted packing means on said sleeve structure adapted to be expandedinto sealing contact with a well bore wall, said fluid passageway beingin communication with the well bore above said packing means; normallyretracted slip means; expander means movable downwardly relative to saidslip means for expanding said slip means outwardly into grippingengagement with a well bore wall; releasable means responsive tomanipulaion of the running-in string for securing said packing means andslip means in retracted and expanded positions; a plurality of pressureresponsive piston members sealingly slidable on said sleeve structure;and means for coupling said piston members to said expander cone inconjoii t force transmitting relationship thereto, each of said pistonmembers having upwardly facing pressure surfaces subject to fluidpressure in the well bore below said packing means and downwardly facingpressure surfaces in communication with said passageway, so that saiddownwardly facing surfaces are subject to fluid pressure in the Wellbore above said packing means, whereby a greater fluid pressure in thewell bore below said packing meaps than above said packing means forcessaid expander means downwardly with a force which is multiplied by thenumber of said piston members.

7. The well packer apparatus of claim 6 wherein said piston members andsaid packing means are mounted on a same diametered portion of saidsleeve structure.

8. The well packer apparatus of claim 6 wherein said body member has afluid bypass passage therein; and valve means for opening and closingsaid bypass passageway.

9. The well packer apparatus of claim 6 further including transversemembers located below each of said piston members and sealed withrespect to said coupling means for preventing fluid communicationbetween said downwardly facing pressure surfaces and the well bore belowsaid packing means.

10. The well packer apparatus of claim 9 wherein one of said transversemembers is mounted on said sleeve structure and the other of saidtransverse members is mounted on said body member.

References Cited UNITED STATES PATENTS 3,233,675 2/1966 Tamplen et al.l66, 3,288,219 11/1966 Young et a1. 166-120 3,338,308 8/1967 Elliston etal. 16612O 3,361,207 1/1968 Chenowcth 166 -120 3,399,729 9/1968 McGill166120 3,412,801 1l/1968 Young 166-120 3,412,802 11/1968 Kisling 166l203,426,846 2/1969 Young 166--l20 X 3,437,136 4/1969 Young 166l20 DAVID H.BROWN, Primary Examiner US. Cl. X.R. 166-133,

